Delta Air Lines said Thursday it is taking a minority stake in private aviation start-up Wheels Up, in a move that establishes one of the world's largest fleets of private aircraft.

Once the transaction is approved, which is expected in early 2020, Wheels Up will have a fleet of 190 planes and more than 8,000 customers, Delta said.

"This groundbreaking partnership will democratize private aviation — making the convenience of private jet travel accessible to more consumers," Delta CEO Ed Bastian said in a statement. He added that the agreement "is the latest step in Delta's ongoing effort to build partnerships that extend Delta's brand beyond its core business."

The company declined to disclose financial terms but said it expected no impact to its 2019 financial guidance. Delta will also hold an equity position in Wheels Up, which said in August that it had completed a $128 million round of funding that valued the company at $1.1 billion.

"It's a way for us to extend our brand and our ability into a new space," Bastian told CNBC's Phil LeBeau in a "Squawk Box" interview from the airline's investor day in Atlanta.

Industry giants such as VistaJet, Directional Aviation and Wheels Up are vying to become the dominant players in the industry.

"To partner with the No. 1 airline in the world ... that's incredible validation for Wheel's Up," the company's founder and CEO Kenny Dichter told CNBC.